RF Coverage Comparison

Post date: Jul 09, 2012 1:56:17 AM

The recent move of LCARA's 2m & 70cm repeaters (and subsequent change in coverage area) have spawned a lot of discussions about RF coverage of various locations. I decided to produce predictive coverage maps for several locations of interest to me, and I share the results here.

For some reason, Google messes with the above image, and doesn't display the GIF animation unless you click on the picture to open it separately.

A more complete (larger area, w/ labels) animation can be downloaded below, along with the individual frames in PNG format that you can do more with, e.g. throw in a directory and use your favorite image browser to view, or load them into web browser tabs so you can easily switch back and forth between any two.

I used the same parameters for each site, modelling a typical 2m base antenna.

The sites I compared are:

• 1. My house (maybe nobody else is interested in that site, but *I* am!)

  2. The LCARA club house (Columbia Hts. -- where the repeaters used to be).

  3. A friend up on Mt. Pleasant

  4. A friend up on N. Green Mtn.

  5. A ham further up Green Mtn.

I didn't model the new repeater site, because I'm still not clear on where it is.

Some observations:

• • I have the best coverage of Mt. St. Helens. (Big "whoopee!" there)

  • The club house provides decent coverage in all directions, with esp. solid signal right around Longview.

  • Mt. Pleasant improves coverage to the SE, loses the NE, and is otherwise fairly similar to Lone Oak.

  • Either location on Green Mtn. has superior coverage to the south, but loses the east. Whether losing the wilderness area is important or not depends on whether or not you're the one stuck out there.

  • A small difference in location on Green Mtn. makes a big difference! Portland is blanketed by the upper location, and coverage towards Centralia is especially enhanced over the site further down the south face.

Any other conclusions to draw from these maps? Sign in and leave a comment, or drop me an email!

2012-07-21: Now if I just climbed to the 2200' level of Woolford Mtn, on whose foothill my house sits, I could rule this magnificent radio kingdom: